GCOVProfiling.cpp revision 363496 
1//===- GCOVProfiling.cpp - Insert edge counters for gcov profiling --------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// This pass implements GCOV-style profiling. When this pass is run it emits
10// "gcno" files next to the existing source, and instruments the code that runs
11// to records the edges between blocks that run and emit a complementary "gcda"
12// file on exit.
13//
14//===----------------------------------------------------------------------===//
15
16#include "llvm/ADT/DenseMap.h"
17#include "llvm/ADT/Hashing.h"
18#include "llvm/ADT/STLExtras.h"
19#include "llvm/ADT/Sequence.h"
20#include "llvm/ADT/Statistic.h"
21#include "llvm/ADT/StringExtras.h"
22#include "llvm/ADT/StringMap.h"
23#include "llvm/Analysis/EHPersonalities.h"
24#include "llvm/Analysis/TargetLibraryInfo.h"
25#include "llvm/IR/CFG.h"
26#include "llvm/IR/DebugInfo.h"
27#include "llvm/IR/DebugLoc.h"
28#include "llvm/IR/IRBuilder.h"
29#include "llvm/IR/InstIterator.h"
30#include "llvm/IR/Instructions.h"
31#include "llvm/IR/IntrinsicInst.h"
32#include "llvm/IR/Module.h"
33#include "llvm/InitializePasses.h"
34#include "llvm/Pass.h"
35#include "llvm/Support/CommandLine.h"
36#include "llvm/Support/Debug.h"
37#include "llvm/Support/FileSystem.h"
38#include "llvm/Support/Path.h"
39#include "llvm/Support/Regex.h"
40#include "llvm/Support/raw_ostream.h"
41#include "llvm/Transforms/Instrumentation.h"
42#include "llvm/Transforms/Instrumentation/GCOVProfiler.h"
43#include "llvm/Transforms/Utils/ModuleUtils.h"
44#include <algorithm>
45#include <memory>
46#include <string>
47#include <utility>
48using namespace llvm;
49
50#define DEBUG_TYPE "insert-gcov-profiling"
51
52static cl::opt<std::string>
53DefaultGCOVVersion("default-gcov-version", cl::init("402*"), cl::Hidden,
54                   cl::ValueRequired);
55static cl::opt<bool> DefaultExitBlockBeforeBody("gcov-exit-block-before-body",
56                                                cl::init(false), cl::Hidden);
57
58GCOVOptions GCOVOptions::getDefault() {
59  GCOVOptions Options;
60  Options.EmitNotes = true;
61  Options.EmitData = true;
62  Options.UseCfgChecksum = false;
63  Options.NoRedZone = false;
64  Options.FunctionNamesInData = true;
65  Options.ExitBlockBeforeBody = DefaultExitBlockBeforeBody;
66
67  if (DefaultGCOVVersion.size() != 4) {
68    llvm::report_fatal_error(std::string("Invalid -default-gcov-version: ") +
69                             DefaultGCOVVersion);
70  }
71  memcpy(Options.Version, DefaultGCOVVersion.c_str(), 4);
72  return Options;
73}
74
75namespace {
76class GCOVFunction;
77
78class GCOVProfiler {
79public:
80  GCOVProfiler() : GCOVProfiler(GCOVOptions::getDefault()) {}
81  GCOVProfiler(const GCOVOptions &Opts) : Options(Opts) {
82    assert((Options.EmitNotes || Options.EmitData) &&
83           "GCOVProfiler asked to do nothing?");
84    ReversedVersion[0] = Options.Version[3];
85    ReversedVersion[1] = Options.Version[2];
86    ReversedVersion[2] = Options.Version[1];
87    ReversedVersion[3] = Options.Version[0];
88    ReversedVersion[4] = '\0';
89  }
90  bool
91  runOnModule(Module &M,
92              std::function<const TargetLibraryInfo &(Function &F)> GetTLI);
93
94private:
95  // Create the .gcno files for the Module based on DebugInfo.
96  void emitProfileNotes();
97
98  // Modify the program to track transitions along edges and call into the
99  // profiling runtime to emit .gcda files when run.
100  bool emitProfileArcs();
101
102  bool isFunctionInstrumented(const Function &F);
103  std::vector<Regex> createRegexesFromString(StringRef RegexesStr);
104  static bool doesFilenameMatchARegex(StringRef Filename,
105                                      std::vector<Regex> &Regexes);
106
107  // Get pointers to the functions in the runtime library.
108  FunctionCallee getStartFileFunc(const TargetLibraryInfo *TLI);
109  FunctionCallee getEmitFunctionFunc(const TargetLibraryInfo *TLI);
110  FunctionCallee getEmitArcsFunc(const TargetLibraryInfo *TLI);
111  FunctionCallee getSummaryInfoFunc();
112  FunctionCallee getEndFileFunc();
113
114  // Add the function to write out all our counters to the global destructor
115  // list.
116  Function *
117  insertCounterWriteout(ArrayRef<std::pair<GlobalVariable *, MDNode *>>);
118  Function *insertReset(ArrayRef<std::pair<GlobalVariable *, MDNode *>>);
119  Function *insertFlush(Function *ResetF);
120
121  void AddFlushBeforeForkAndExec();
122
123  enum class GCovFileType { GCNO, GCDA };
124  std::string mangleName(const DICompileUnit *CU, GCovFileType FileType);
125
126  GCOVOptions Options;
127
128  // Reversed, NUL-terminated copy of Options.Version.
129  char ReversedVersion[5];
130  // Checksum, produced by hash of EdgeDestinations
131  SmallVector<uint32_t, 4> FileChecksums;
132
133  Module *M = nullptr;
134  std::function<const TargetLibraryInfo &(Function &F)> GetTLI;
135  LLVMContext *Ctx = nullptr;
136  SmallVector<std::unique_ptr<GCOVFunction>, 16> Funcs;
137  std::vector<Regex> FilterRe;
138  std::vector<Regex> ExcludeRe;
139  StringMap<bool> InstrumentedFiles;
140};
141
142class GCOVProfilerLegacyPass : public ModulePass {
143public:
144  static char ID;
145  GCOVProfilerLegacyPass()
146      : GCOVProfilerLegacyPass(GCOVOptions::getDefault()) {}
147  GCOVProfilerLegacyPass(const GCOVOptions &Opts)
148      : ModulePass(ID), Profiler(Opts) {
149    initializeGCOVProfilerLegacyPassPass(*PassRegistry::getPassRegistry());
150  }
151  StringRef getPassName() const override { return "GCOV Profiler"; }
152
153  bool runOnModule(Module &M) override {
154    return Profiler.runOnModule(M, [this](Function &F) -> TargetLibraryInfo & {
155      return getAnalysis<TargetLibraryInfoWrapperPass>().getTLI(F);
156    });
157  }
158
159  void getAnalysisUsage(AnalysisUsage &AU) const override {
160    AU.addRequired<TargetLibraryInfoWrapperPass>();
161  }
162
163private:
164  GCOVProfiler Profiler;
165};
166}
167
168char GCOVProfilerLegacyPass::ID = 0;
169INITIALIZE_PASS_BEGIN(
170    GCOVProfilerLegacyPass, "insert-gcov-profiling",
171    "Insert instrumentation for GCOV profiling", false, false)
172INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfoWrapperPass)
173INITIALIZE_PASS_END(
174    GCOVProfilerLegacyPass, "insert-gcov-profiling",
175    "Insert instrumentation for GCOV profiling", false, false)
176
177ModulePass *llvm::createGCOVProfilerPass(const GCOVOptions &Options) {
178  return new GCOVProfilerLegacyPass(Options);
179}
180
181static StringRef getFunctionName(const DISubprogram *SP) {
182  if (!SP->getLinkageName().empty())
183    return SP->getLinkageName();
184  return SP->getName();
185}
186
187/// Extract a filename for a DISubprogram.
188///
189/// Prefer relative paths in the coverage notes. Clang also may split
190/// up absolute paths into a directory and filename component. When
191/// the relative path doesn't exist, reconstruct the absolute path.
192static SmallString<128> getFilename(const DISubprogram *SP) {
193  SmallString<128> Path;
194  StringRef RelPath = SP->getFilename();
195  if (sys::fs::exists(RelPath))
196    Path = RelPath;
197  else
198    sys::path::append(Path, SP->getDirectory(), SP->getFilename());
199  return Path;
200}
201
202namespace {
203  class GCOVRecord {
204   protected:
205    static const char *const LinesTag;
206    static const char *const FunctionTag;
207    static const char *const BlockTag;
208    static const char *const EdgeTag;
209
210    GCOVRecord() = default;
211
212    void writeBytes(const char *Bytes, int Size) {
213      os->write(Bytes, Size);
214    }
215
216    void write(uint32_t i) {
217      writeBytes(reinterpret_cast<char*>(&i), 4);
218    }
219
220    // Returns the length measured in 4-byte blocks that will be used to
221    // represent this string in a GCOV file
222    static unsigned lengthOfGCOVString(StringRef s) {
223      // A GCOV string is a length, followed by a NUL, then between 0 and 3 NULs
224      // padding out to the next 4-byte word. The length is measured in 4-byte
225      // words including padding, not bytes of actual string.
226      return (s.size() / 4) + 1;
227    }
228
229    void writeGCOVString(StringRef s) {
230      uint32_t Len = lengthOfGCOVString(s);
231      write(Len);
232      writeBytes(s.data(), s.size());
233
234      // Write 1 to 4 bytes of NUL padding.
235      assert((unsigned)(4 - (s.size() % 4)) > 0);
236      assert((unsigned)(4 - (s.size() % 4)) <= 4);
237      writeBytes("\0\0\0\0", 4 - (s.size() % 4));
238    }
239
240    raw_ostream *os;
241  };
242  const char *const GCOVRecord::LinesTag = "\0\0\x45\x01";
243  const char *const GCOVRecord::FunctionTag = "\0\0\0\1";
244  const char *const GCOVRecord::BlockTag = "\0\0\x41\x01";
245  const char *const GCOVRecord::EdgeTag = "\0\0\x43\x01";
246
247  class GCOVFunction;
248  class GCOVBlock;
249
250  // Constructed only by requesting it from a GCOVBlock, this object stores a
251  // list of line numbers and a single filename, representing lines that belong
252  // to the block.
253  class GCOVLines : public GCOVRecord {
254   public:
255    void addLine(uint32_t Line) {
256      assert(Line != 0 && "Line zero is not a valid real line number.");
257      Lines.push_back(Line);
258    }
259
260    uint32_t length() const {
261      // Here 2 = 1 for string length + 1 for '0' id#.
262      return lengthOfGCOVString(Filename) + 2 + Lines.size();
263    }
264
265    void writeOut() {
266      write(0);
267      writeGCOVString(Filename);
268      for (int i = 0, e = Lines.size(); i != e; ++i)
269        write(Lines[i]);
270    }
271
272    GCOVLines(StringRef F, raw_ostream *os)
273      : Filename(F) {
274      this->os = os;
275    }
276
277   private:
278    std::string Filename;
279    SmallVector<uint32_t, 32> Lines;
280  };
281
282
283  // Represent a basic block in GCOV. Each block has a unique number in the
284  // function, number of lines belonging to each block, and a set of edges to
285  // other blocks.
286  class GCOVBlock : public GCOVRecord {
287   public:
288    GCOVLines &getFile(StringRef Filename) {
289      return LinesByFile.try_emplace(Filename, Filename, os).first->second;
290    }
291
292    void addEdge(GCOVBlock &Successor) {
293      OutEdges.push_back(&Successor);
294    }
295
296    void writeOut() {
297      uint32_t Len = 3;
298      SmallVector<StringMapEntry<GCOVLines> *, 32> SortedLinesByFile;
299      for (auto &I : LinesByFile) {
300        Len += I.second.length();
301        SortedLinesByFile.push_back(&I);
302      }
303
304      writeBytes(LinesTag, 4);
305      write(Len);
306      write(Number);
307
308      llvm::sort(SortedLinesByFile, [](StringMapEntry<GCOVLines> *LHS,
309                                       StringMapEntry<GCOVLines> *RHS) {
310        return LHS->getKey() < RHS->getKey();
311      });
312      for (auto &I : SortedLinesByFile)
313        I->getValue().writeOut();
314      write(0);
315      write(0);
316    }
317
318    GCOVBlock(const GCOVBlock &RHS) : GCOVRecord(RHS), Number(RHS.Number) {
319      // Only allow copy before edges and lines have been added. After that,
320      // there are inter-block pointers (eg: edges) that won't take kindly to
321      // blocks being copied or moved around.
322      assert(LinesByFile.empty());
323      assert(OutEdges.empty());
324    }
325
326   private:
327    friend class GCOVFunction;
328
329    GCOVBlock(uint32_t Number, raw_ostream *os)
330        : Number(Number) {
331      this->os = os;
332    }
333
334    uint32_t Number;
335    StringMap<GCOVLines> LinesByFile;
336    SmallVector<GCOVBlock *, 4> OutEdges;
337  };
338
339  // A function has a unique identifier, a checksum (we leave as zero) and a
340  // set of blocks and a map of edges between blocks. This is the only GCOV
341  // object users can construct, the blocks and lines will be rooted here.
342  class GCOVFunction : public GCOVRecord {
343   public:
344     GCOVFunction(const DISubprogram *SP, Function *F, raw_ostream *os,
345                  uint32_t Ident, bool UseCfgChecksum, bool ExitBlockBeforeBody)
346         : SP(SP), Ident(Ident), UseCfgChecksum(UseCfgChecksum), CfgChecksum(0),
347           ReturnBlock(1, os) {
348      this->os = os;
349
350      LLVM_DEBUG(dbgs() << "Function: " << getFunctionName(SP) << "\n");
351
352      uint32_t i = 0;
353      for (auto &BB : *F) {
354        // Skip index 1 if it's assigned to the ReturnBlock.
355        if (i == 1 && ExitBlockBeforeBody)
356          ++i;
357        Blocks.insert(std::make_pair(&BB, GCOVBlock(i++, os)));
358      }
359      if (!ExitBlockBeforeBody)
360        ReturnBlock.Number = i;
361
362      std::string FunctionNameAndLine;
363      raw_string_ostream FNLOS(FunctionNameAndLine);
364      FNLOS << getFunctionName(SP) << SP->getLine();
365      FNLOS.flush();
366      FuncChecksum = hash_value(FunctionNameAndLine);
367    }
368
369    GCOVBlock &getBlock(BasicBlock *BB) {
370      return Blocks.find(BB)->second;
371    }
372
373    GCOVBlock &getReturnBlock() {
374      return ReturnBlock;
375    }
376
377    std::string getEdgeDestinations() {
378      std::string EdgeDestinations;
379      raw_string_ostream EDOS(EdgeDestinations);
380      Function *F = Blocks.begin()->first->getParent();
381      for (BasicBlock &I : *F) {
382        GCOVBlock &Block = getBlock(&I);
383        for (int i = 0, e = Block.OutEdges.size(); i != e; ++i)
384          EDOS << Block.OutEdges[i]->Number;
385      }
386      return EdgeDestinations;
387    }
388
389    uint32_t getFuncChecksum() const {
390      return FuncChecksum;
391    }
392
393    void setCfgChecksum(uint32_t Checksum) {
394      CfgChecksum = Checksum;
395    }
396
397    void writeOut() {
398      writeBytes(FunctionTag, 4);
399      SmallString<128> Filename = getFilename(SP);
400      uint32_t BlockLen = 1 + 1 + 1 + lengthOfGCOVString(getFunctionName(SP)) +
401                          1 + lengthOfGCOVString(Filename) + 1;
402      if (UseCfgChecksum)
403        ++BlockLen;
404      write(BlockLen);
405      write(Ident);
406      write(FuncChecksum);
407      if (UseCfgChecksum)
408        write(CfgChecksum);
409      writeGCOVString(getFunctionName(SP));
410      writeGCOVString(Filename);
411      write(SP->getLine());
412
413      // Emit count of blocks.
414      writeBytes(BlockTag, 4);
415      write(Blocks.size() + 1);
416      for (int i = 0, e = Blocks.size() + 1; i != e; ++i) {
417        write(0);  // No flags on our blocks.
418      }
419      LLVM_DEBUG(dbgs() << Blocks.size() << " blocks.\n");
420
421      // Emit edges between blocks.
422      if (Blocks.empty()) return;
423      Function *F = Blocks.begin()->first->getParent();
424      for (BasicBlock &I : *F) {
425        GCOVBlock &Block = getBlock(&I);
426        if (Block.OutEdges.empty()) continue;
427
428        writeBytes(EdgeTag, 4);
429        write(Block.OutEdges.size() * 2 + 1);
430        write(Block.Number);
431        for (int i = 0, e = Block.OutEdges.size(); i != e; ++i) {
432          LLVM_DEBUG(dbgs() << Block.Number << " -> "
433                            << Block.OutEdges[i]->Number << "\n");
434          write(Block.OutEdges[i]->Number);
435          write(0);  // no flags
436        }
437      }
438
439      // Emit lines for each block.
440      for (BasicBlock &I : *F)
441        getBlock(&I).writeOut();
442    }
443
444   private:
445     const DISubprogram *SP;
446    uint32_t Ident;
447    uint32_t FuncChecksum;
448    bool UseCfgChecksum;
449    uint32_t CfgChecksum;
450    DenseMap<BasicBlock *, GCOVBlock> Blocks;
451    GCOVBlock ReturnBlock;
452  };
453}
454
455// RegexesStr is a string containing differents regex separated by a semi-colon.
456// For example "foo\..*$;bar\..*$".
457std::vector<Regex> GCOVProfiler::createRegexesFromString(StringRef RegexesStr) {
458  std::vector<Regex> Regexes;
459  while (!RegexesStr.empty()) {
460    std::pair<StringRef, StringRef> HeadTail = RegexesStr.split(';');
461    if (!HeadTail.first.empty()) {
462      Regex Re(HeadTail.first);
463      std::string Err;
464      if (!Re.isValid(Err)) {
465        Ctx->emitError(Twine("Regex ") + HeadTail.first +
466                       " is not valid: " + Err);
467      }
468      Regexes.emplace_back(std::move(Re));
469    }
470    RegexesStr = HeadTail.second;
471  }
472  return Regexes;
473}
474
475bool GCOVProfiler::doesFilenameMatchARegex(StringRef Filename,
476                                           std::vector<Regex> &Regexes) {
477  for (Regex &Re : Regexes) {
478    if (Re.match(Filename)) {
479      return true;
480    }
481  }
482  return false;
483}
484
485bool GCOVProfiler::isFunctionInstrumented(const Function &F) {
486  if (FilterRe.empty() && ExcludeRe.empty()) {
487    return true;
488  }
489  SmallString<128> Filename = getFilename(F.getSubprogram());
490  auto It = InstrumentedFiles.find(Filename);
491  if (It != InstrumentedFiles.end()) {
492    return It->second;
493  }
494
495  SmallString<256> RealPath;
496  StringRef RealFilename;
497
498  // Path can be
499  // /usr/lib/gcc/x86_64-linux-gnu/8/../../../../include/c++/8/bits/*.h so for
500  // such a case we must get the real_path.
501  if (sys::fs::real_path(Filename, RealPath)) {
502    // real_path can fail with path like "foo.c".
503    RealFilename = Filename;
504  } else {
505    RealFilename = RealPath;
506  }
507
508  bool ShouldInstrument;
509  if (FilterRe.empty()) {
510    ShouldInstrument = !doesFilenameMatchARegex(RealFilename, ExcludeRe);
511  } else if (ExcludeRe.empty()) {
512    ShouldInstrument = doesFilenameMatchARegex(RealFilename, FilterRe);
513  } else {
514    ShouldInstrument = doesFilenameMatchARegex(RealFilename, FilterRe) &&
515                       !doesFilenameMatchARegex(RealFilename, ExcludeRe);
516  }
517  InstrumentedFiles[Filename] = ShouldInstrument;
518  return ShouldInstrument;
519}
520
521std::string GCOVProfiler::mangleName(const DICompileUnit *CU,
522                                     GCovFileType OutputType) {
523  bool Notes = OutputType == GCovFileType::GCNO;
524
525  if (NamedMDNode *GCov = M->getNamedMetadata("llvm.gcov")) {
526    for (int i = 0, e = GCov->getNumOperands(); i != e; ++i) {
527      MDNode *N = GCov->getOperand(i);
528      bool ThreeElement = N->getNumOperands() == 3;
529      if (!ThreeElement && N->getNumOperands() != 2)
530        continue;
531      if (dyn_cast<MDNode>(N->getOperand(ThreeElement ? 2 : 1)) != CU)
532        continue;
533
534      if (ThreeElement) {
535        // These nodes have no mangling to apply, it's stored mangled in the
536        // bitcode.
537        MDString *NotesFile = dyn_cast<MDString>(N->getOperand(0));
538        MDString *DataFile = dyn_cast<MDString>(N->getOperand(1));
539        if (!NotesFile || !DataFile)
540          continue;
541        return Notes ? NotesFile->getString() : DataFile->getString();
542      }
543
544      MDString *GCovFile = dyn_cast<MDString>(N->getOperand(0));
545      if (!GCovFile)
546        continue;
547
548      SmallString<128> Filename = GCovFile->getString();
549      sys::path::replace_extension(Filename, Notes ? "gcno" : "gcda");
550      return Filename.str();
551    }
552  }
553
554  SmallString<128> Filename = CU->getFilename();
555  sys::path::replace_extension(Filename, Notes ? "gcno" : "gcda");
556  StringRef FName = sys::path::filename(Filename);
557  SmallString<128> CurPath;
558  if (sys::fs::current_path(CurPath)) return FName;
559  sys::path::append(CurPath, FName);
560  return CurPath.str();
561}
562
563bool GCOVProfiler::runOnModule(
564    Module &M, std::function<const TargetLibraryInfo &(Function &F)> GetTLI) {
565  this->M = &M;
566  this->GetTLI = std::move(GetTLI);
567  Ctx = &M.getContext();
568
569  AddFlushBeforeForkAndExec();
570
571  FilterRe = createRegexesFromString(Options.Filter);
572  ExcludeRe = createRegexesFromString(Options.Exclude);
573
574  if (Options.EmitNotes) emitProfileNotes();
575  if (Options.EmitData) return emitProfileArcs();
576  return false;
577}
578
579PreservedAnalyses GCOVProfilerPass::run(Module &M,
580                                        ModuleAnalysisManager &AM) {
581
582  GCOVProfiler Profiler(GCOVOpts);
583  FunctionAnalysisManager &FAM =
584      AM.getResult<FunctionAnalysisManagerModuleProxy>(M).getManager();
585
586  if (!Profiler.runOnModule(M, [&](Function &F) -> TargetLibraryInfo & {
587        return FAM.getResult<TargetLibraryAnalysis>(F);
588      }))
589    return PreservedAnalyses::all();
590
591  return PreservedAnalyses::none();
592}
593
594static bool functionHasLines(Function &F) {
595  // Check whether this function actually has any source lines. Not only
596  // do these waste space, they also can crash gcov.
597  for (auto &BB : F) {
598    for (auto &I : BB) {
599      // Debug intrinsic locations correspond to the location of the
600      // declaration, not necessarily any statements or expressions.
601      if (isa<DbgInfoIntrinsic>(&I)) continue;
602
603      const DebugLoc &Loc = I.getDebugLoc();
604      if (!Loc)
605        continue;
606
607      // Artificial lines such as calls to the global constructors.
608      if (Loc.getLine() == 0) continue;
609
610      return true;
611    }
612  }
613  return false;
614}
615
616static bool isUsingScopeBasedEH(Function &F) {
617  if (!F.hasPersonalityFn()) return false;
618
619  EHPersonality Personality = classifyEHPersonality(F.getPersonalityFn());
620  return isScopedEHPersonality(Personality);
621}
622
623static bool shouldKeepInEntry(BasicBlock::iterator It) {
624	if (isa<AllocaInst>(*It)) return true;
625	if (isa<DbgInfoIntrinsic>(*It)) return true;
626	if (auto *II = dyn_cast<IntrinsicInst>(It)) {
627		if (II->getIntrinsicID() == llvm::Intrinsic::localescape) return true;
628	}
629
630	return false;
631}
632
633void GCOVProfiler::AddFlushBeforeForkAndExec() {
634  SmallVector<CallInst *, 2> Forks;
635  SmallVector<CallInst *, 2> Execs;
636  for (auto &F : M->functions()) {
637    auto *TLI = &GetTLI(F);
638    for (auto &I : instructions(F)) {
639      if (CallInst *CI = dyn_cast<CallInst>(&I)) {
640        if (Function *Callee = CI->getCalledFunction()) {
641          LibFunc LF;
642          if (TLI->getLibFunc(*Callee, LF)) {
643            if (LF == LibFunc_fork) {
644#if !defined(_WIN32)
645              Forks.push_back(CI);
646#endif
647            } else if (LF == LibFunc_execl || LF == LibFunc_execle ||
648                       LF == LibFunc_execlp || LF == LibFunc_execv ||
649                       LF == LibFunc_execvp || LF == LibFunc_execve ||
650                       LF == LibFunc_execvpe || LF == LibFunc_execvP) {
651              Execs.push_back(CI);
652            }
653          }
654        }
655      }
656    }
657  }
658
659  for (auto F : Forks) {
660    IRBuilder<> Builder(F);
661    BasicBlock *Parent = F->getParent();
662    auto NextInst = ++F->getIterator();
663
664    // We've a fork so just reset the counters in the child process
665    FunctionType *FTy = FunctionType::get(Builder.getInt32Ty(), {}, false);
666    FunctionCallee GCOVFork = M->getOrInsertFunction("__gcov_fork", FTy);
667    F->setCalledFunction(GCOVFork);
668
669    // We split just after the fork to have a counter for the lines after
670    // Anyway there's a bug:
671    // void foo() { fork(); }
672    // void bar() { foo(); blah(); }
673    // then "blah();" will be called 2 times but showed as 1
674    // because "blah()" belongs to the same block as "foo();"
675    Parent->splitBasicBlock(NextInst);
676
677    // back() is a br instruction with a debug location
678    // equals to the one from NextAfterFork
679    // So to avoid to have two debug locs on two blocks just change it
680    DebugLoc Loc = F->getDebugLoc();
681    Parent->back().setDebugLoc(Loc);
682  }
683
684  for (auto E : Execs) {
685    IRBuilder<> Builder(E);
686    BasicBlock *Parent = E->getParent();
687    auto NextInst = ++E->getIterator();
688
689    // Since the process is replaced by a new one we need to write out gcdas
690    // No need to reset the counters since they'll be lost after the exec**
691    FunctionType *FTy = FunctionType::get(Builder.getVoidTy(), {}, false);
692    FunctionCallee WriteoutF =
693        M->getOrInsertFunction("llvm_writeout_files", FTy);
694    Builder.CreateCall(WriteoutF);
695
696    DebugLoc Loc = E->getDebugLoc();
697    Builder.SetInsertPoint(&*NextInst);
698    // If the exec** fails we must reset the counters since they've been
699    // dumped
700    FunctionCallee ResetF = M->getOrInsertFunction("llvm_reset_counters", FTy);
701    Builder.CreateCall(ResetF)->setDebugLoc(Loc);
702    Parent->splitBasicBlock(NextInst);
703    Parent->back().setDebugLoc(Loc);
704  }
705}
706
707void GCOVProfiler::emitProfileNotes() {
708  NamedMDNode *CU_Nodes = M->getNamedMetadata("llvm.dbg.cu");
709  if (!CU_Nodes) return;
710
711  for (unsigned i = 0, e = CU_Nodes->getNumOperands(); i != e; ++i) {
712    // Each compile unit gets its own .gcno file. This means that whether we run
713    // this pass over the original .o's as they're produced, or run it after
714    // LTO, we'll generate the same .gcno files.
715
716    auto *CU = cast<DICompileUnit>(CU_Nodes->getOperand(i));
717
718    // Skip module skeleton (and module) CUs.
719    if (CU->getDWOId())
720      continue;
721
722    std::error_code EC;
723    raw_fd_ostream out(mangleName(CU, GCovFileType::GCNO), EC,
724                       sys::fs::OF_None);
725    if (EC) {
726      Ctx->emitError(Twine("failed to open coverage notes file for writing: ") +
727                     EC.message());
728      continue;
729    }
730
731    std::string EdgeDestinations;
732
733    unsigned FunctionIdent = 0;
734    for (auto &F : M->functions()) {
735      DISubprogram *SP = F.getSubprogram();
736      if (!SP) continue;
737      if (!functionHasLines(F) || !isFunctionInstrumented(F))
738        continue;
739      // TODO: Functions using scope-based EH are currently not supported.
740      if (isUsingScopeBasedEH(F)) continue;
741
742      // gcov expects every function to start with an entry block that has a
743      // single successor, so split the entry block to make sure of that.
744      BasicBlock &EntryBlock = F.getEntryBlock();
745      BasicBlock::iterator It = EntryBlock.begin();
746      while (shouldKeepInEntry(It))
747        ++It;
748      EntryBlock.splitBasicBlock(It);
749
750      Funcs.push_back(std::make_unique<GCOVFunction>(SP, &F, &out, FunctionIdent++,
751                                                Options.UseCfgChecksum,
752                                                Options.ExitBlockBeforeBody));
753      GCOVFunction &Func = *Funcs.back();
754
755      // Add the function line number to the lines of the entry block
756      // to have a counter for the function definition.
757      uint32_t Line = SP->getLine();
758      auto Filename = getFilename(SP);
759
760      // Artificial functions such as global initializers
761      if (!SP->isArtificial())
762        Func.getBlock(&EntryBlock).getFile(Filename).addLine(Line);
763
764      for (auto &BB : F) {
765        GCOVBlock &Block = Func.getBlock(&BB);
766        Instruction *TI = BB.getTerminator();
767        if (int successors = TI->getNumSuccessors()) {
768          for (int i = 0; i != successors; ++i) {
769            Block.addEdge(Func.getBlock(TI->getSuccessor(i)));
770          }
771        } else if (isa<ReturnInst>(TI)) {
772          Block.addEdge(Func.getReturnBlock());
773        }
774
775        for (auto &I : BB) {
776          // Debug intrinsic locations correspond to the location of the
777          // declaration, not necessarily any statements or expressions.
778          if (isa<DbgInfoIntrinsic>(&I)) continue;
779
780          const DebugLoc &Loc = I.getDebugLoc();
781          if (!Loc)
782            continue;
783
784          // Artificial lines such as calls to the global constructors.
785          if (Loc.getLine() == 0 || Loc.isImplicitCode())
786            continue;
787
788          if (Line == Loc.getLine()) continue;
789          Line = Loc.getLine();
790          if (SP != getDISubprogram(Loc.getScope()))
791            continue;
792
793          GCOVLines &Lines = Block.getFile(Filename);
794          Lines.addLine(Loc.getLine());
795        }
796        Line = 0;
797      }
798      EdgeDestinations += Func.getEdgeDestinations();
799    }
800
801    FileChecksums.push_back(hash_value(EdgeDestinations));
802    out.write("oncg", 4);
803    out.write(ReversedVersion, 4);
804    out.write(reinterpret_cast<char*>(&FileChecksums.back()), 4);
805
806    for (auto &Func : Funcs) {
807      Func->setCfgChecksum(FileChecksums.back());
808      Func->writeOut();
809    }
810
811    out.write("\0\0\0\0\0\0\0\0", 8);  // EOF
812    out.close();
813  }
814}
815
816bool GCOVProfiler::emitProfileArcs() {
817  NamedMDNode *CU_Nodes = M->getNamedMetadata("llvm.dbg.cu");
818  if (!CU_Nodes) return false;
819
820  bool Result = false;
821  for (unsigned i = 0, e = CU_Nodes->getNumOperands(); i != e; ++i) {
822    SmallVector<std::pair<GlobalVariable *, MDNode *>, 8> CountersBySP;
823    for (auto &F : M->functions()) {
824      DISubprogram *SP = F.getSubprogram();
825      if (!SP) continue;
826      if (!functionHasLines(F) || !isFunctionInstrumented(F))
827        continue;
828      // TODO: Functions using scope-based EH are currently not supported.
829      if (isUsingScopeBasedEH(F)) continue;
830      if (!Result) Result = true;
831
832      DenseMap<std::pair<BasicBlock *, BasicBlock *>, unsigned> EdgeToCounter;
833      unsigned Edges = 0;
834      for (auto &BB : F) {
835        Instruction *TI = BB.getTerminator();
836        if (isa<ReturnInst>(TI)) {
837          EdgeToCounter[{&BB, nullptr}] = Edges++;
838        } else {
839          for (BasicBlock *Succ : successors(TI)) {
840            EdgeToCounter[{&BB, Succ}] = Edges++;
841          }
842        }
843      }
844
845      ArrayType *CounterTy =
846        ArrayType::get(Type::getInt64Ty(*Ctx), Edges);
847      GlobalVariable *Counters =
848        new GlobalVariable(*M, CounterTy, false,
849                           GlobalValue::InternalLinkage,
850                           Constant::getNullValue(CounterTy),
851                           "__llvm_gcov_ctr");
852      CountersBySP.push_back(std::make_pair(Counters, SP));
853
854      // If a BB has several predecessors, use a PHINode to select
855      // the correct counter.
856      for (auto &BB : F) {
857        const unsigned EdgeCount =
858            std::distance(pred_begin(&BB), pred_end(&BB));
859        if (EdgeCount) {
860          // The phi node must be at the begin of the BB.
861          IRBuilder<> BuilderForPhi(&*BB.begin());
862          Type *Int64PtrTy = Type::getInt64PtrTy(*Ctx);
863          PHINode *Phi = BuilderForPhi.CreatePHI(Int64PtrTy, EdgeCount);
864          for (BasicBlock *Pred : predecessors(&BB)) {
865            auto It = EdgeToCounter.find({Pred, &BB});
866            assert(It != EdgeToCounter.end());
867            const unsigned Edge = It->second;
868            Value *EdgeCounter = BuilderForPhi.CreateConstInBoundsGEP2_64(
869                Counters->getValueType(), Counters, 0, Edge);
870            Phi->addIncoming(EdgeCounter, Pred);
871          }
872
873          // Skip phis, landingpads.
874          IRBuilder<> Builder(&*BB.getFirstInsertionPt());
875          Value *Count = Builder.CreateLoad(Builder.getInt64Ty(), Phi);
876          Count = Builder.CreateAdd(Count, Builder.getInt64(1));
877          Builder.CreateStore(Count, Phi);
878
879          Instruction *TI = BB.getTerminator();
880          if (isa<ReturnInst>(TI)) {
881            auto It = EdgeToCounter.find({&BB, nullptr});
882            assert(It != EdgeToCounter.end());
883            const unsigned Edge = It->second;
884            Value *Counter = Builder.CreateConstInBoundsGEP2_64(
885                Counters->getValueType(), Counters, 0, Edge);
886            Value *Count = Builder.CreateLoad(Builder.getInt64Ty(), Counter);
887            Count = Builder.CreateAdd(Count, Builder.getInt64(1));
888            Builder.CreateStore(Count, Counter);
889          }
890        }
891      }
892    }
893
894    Function *WriteoutF = insertCounterWriteout(CountersBySP);
895    Function *ResetF = insertReset(CountersBySP);
896    Function *FlushF = insertFlush(ResetF);
897
898    // Create a small bit of code that registers the "__llvm_gcov_writeout" to
899    // be executed at exit and the "__llvm_gcov_flush" function to be executed
900    // when "__gcov_flush" is called.
901    FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx), false);
902    Function *F = Function::Create(FTy, GlobalValue::InternalLinkage,
903                                   "__llvm_gcov_init", M);
904    F->setUnnamedAddr(GlobalValue::UnnamedAddr::Global);
905    F->setLinkage(GlobalValue::InternalLinkage);
906    F->addFnAttr(Attribute::NoInline);
907    if (Options.NoRedZone)
908      F->addFnAttr(Attribute::NoRedZone);
909
910    BasicBlock *BB = BasicBlock::Create(*Ctx, "entry", F);
911    IRBuilder<> Builder(BB);
912
913    FTy = FunctionType::get(Type::getVoidTy(*Ctx), false);
914    Type *Params[] = {PointerType::get(FTy, 0), PointerType::get(FTy, 0),
915                      PointerType::get(FTy, 0)};
916    FTy = FunctionType::get(Builder.getVoidTy(), Params, false);
917
918    // Initialize the environment and register the local writeout, flush and
919    // reset functions.
920    FunctionCallee GCOVInit = M->getOrInsertFunction("llvm_gcov_init", FTy);
921    Builder.CreateCall(GCOVInit, {WriteoutF, FlushF, ResetF});
922    Builder.CreateRetVoid();
923
924    appendToGlobalCtors(*M, F, 0);
925  }
926
927  return Result;
928}
929
930FunctionCallee GCOVProfiler::getStartFileFunc(const TargetLibraryInfo *TLI) {
931  Type *Args[] = {
932    Type::getInt8PtrTy(*Ctx),  // const char *orig_filename
933    Type::getInt8PtrTy(*Ctx),  // const char version[4]
934    Type::getInt32Ty(*Ctx),    // uint32_t checksum
935  };
936  FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx), Args, false);
937  AttributeList AL;
938  if (auto AK = TLI->getExtAttrForI32Param(false))
939    AL = AL.addParamAttribute(*Ctx, 2, AK);
940  FunctionCallee Res = M->getOrInsertFunction("llvm_gcda_start_file", FTy, AL);
941  return Res;
942}
943
944FunctionCallee GCOVProfiler::getEmitFunctionFunc(const TargetLibraryInfo *TLI) {
945  Type *Args[] = {
946    Type::getInt32Ty(*Ctx),    // uint32_t ident
947    Type::getInt8PtrTy(*Ctx),  // const char *function_name
948    Type::getInt32Ty(*Ctx),    // uint32_t func_checksum
949    Type::getInt8Ty(*Ctx),     // uint8_t use_extra_checksum
950    Type::getInt32Ty(*Ctx),    // uint32_t cfg_checksum
951  };
952  FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx), Args, false);
953  AttributeList AL;
954  if (auto AK = TLI->getExtAttrForI32Param(false)) {
955    AL = AL.addParamAttribute(*Ctx, 0, AK);
956    AL = AL.addParamAttribute(*Ctx, 2, AK);
957    AL = AL.addParamAttribute(*Ctx, 3, AK);
958    AL = AL.addParamAttribute(*Ctx, 4, AK);
959  }
960  return M->getOrInsertFunction("llvm_gcda_emit_function", FTy);
961}
962
963FunctionCallee GCOVProfiler::getEmitArcsFunc(const TargetLibraryInfo *TLI) {
964  Type *Args[] = {
965    Type::getInt32Ty(*Ctx),     // uint32_t num_counters
966    Type::getInt64PtrTy(*Ctx),  // uint64_t *counters
967  };
968  FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx), Args, false);
969  AttributeList AL;
970  if (auto AK = TLI->getExtAttrForI32Param(false))
971    AL = AL.addParamAttribute(*Ctx, 0, AK);
972  return M->getOrInsertFunction("llvm_gcda_emit_arcs", FTy, AL);
973}
974
975FunctionCallee GCOVProfiler::getSummaryInfoFunc() {
976  FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx), false);
977  return M->getOrInsertFunction("llvm_gcda_summary_info", FTy);
978}
979
980FunctionCallee GCOVProfiler::getEndFileFunc() {
981  FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx), false);
982  return M->getOrInsertFunction("llvm_gcda_end_file", FTy);
983}
984
985Function *GCOVProfiler::insertCounterWriteout(
986    ArrayRef<std::pair<GlobalVariable *, MDNode *> > CountersBySP) {
987  FunctionType *WriteoutFTy = FunctionType::get(Type::getVoidTy(*Ctx), false);
988  Function *WriteoutF = M->getFunction("__llvm_gcov_writeout");
989  if (!WriteoutF)
990    WriteoutF = Function::Create(WriteoutFTy, GlobalValue::InternalLinkage,
991                                 "__llvm_gcov_writeout", M);
992  WriteoutF->setUnnamedAddr(GlobalValue::UnnamedAddr::Global);
993  WriteoutF->addFnAttr(Attribute::NoInline);
994  if (Options.NoRedZone)
995    WriteoutF->addFnAttr(Attribute::NoRedZone);
996
997  BasicBlock *BB = BasicBlock::Create(*Ctx, "entry", WriteoutF);
998  IRBuilder<> Builder(BB);
999
1000  auto *TLI = &GetTLI(*WriteoutF);
1001
1002  FunctionCallee StartFile = getStartFileFunc(TLI);
1003  FunctionCallee EmitFunction = getEmitFunctionFunc(TLI);
1004  FunctionCallee EmitArcs = getEmitArcsFunc(TLI);
1005  FunctionCallee SummaryInfo = getSummaryInfoFunc();
1006  FunctionCallee EndFile = getEndFileFunc();
1007
1008  NamedMDNode *CUNodes = M->getNamedMetadata("llvm.dbg.cu");
1009  if (!CUNodes) {
1010    Builder.CreateRetVoid();
1011    return WriteoutF;
1012  }
1013
1014  // Collect the relevant data into a large constant data structure that we can
1015  // walk to write out everything.
1016  StructType *StartFileCallArgsTy = StructType::create(
1017      {Builder.getInt8PtrTy(), Builder.getInt8PtrTy(), Builder.getInt32Ty()});
1018  StructType *EmitFunctionCallArgsTy = StructType::create(
1019      {Builder.getInt32Ty(), Builder.getInt8PtrTy(), Builder.getInt32Ty(),
1020       Builder.getInt8Ty(), Builder.getInt32Ty()});
1021  StructType *EmitArcsCallArgsTy = StructType::create(
1022      {Builder.getInt32Ty(), Builder.getInt64Ty()->getPointerTo()});
1023  StructType *FileInfoTy =
1024      StructType::create({StartFileCallArgsTy, Builder.getInt32Ty(),
1025                          EmitFunctionCallArgsTy->getPointerTo(),
1026                          EmitArcsCallArgsTy->getPointerTo()});
1027
1028  Constant *Zero32 = Builder.getInt32(0);
1029  // Build an explicit array of two zeros for use in ConstantExpr GEP building.
1030  Constant *TwoZero32s[] = {Zero32, Zero32};
1031
1032  SmallVector<Constant *, 8> FileInfos;
1033  for (int i : llvm::seq<int>(0, CUNodes->getNumOperands())) {
1034    auto *CU = cast<DICompileUnit>(CUNodes->getOperand(i));
1035
1036    // Skip module skeleton (and module) CUs.
1037    if (CU->getDWOId())
1038      continue;
1039
1040    std::string FilenameGcda = mangleName(CU, GCovFileType::GCDA);
1041    uint32_t CfgChecksum = FileChecksums.empty() ? 0 : FileChecksums[i];
1042    auto *StartFileCallArgs = ConstantStruct::get(
1043        StartFileCallArgsTy, {Builder.CreateGlobalStringPtr(FilenameGcda),
1044                              Builder.CreateGlobalStringPtr(ReversedVersion),
1045                              Builder.getInt32(CfgChecksum)});
1046
1047    SmallVector<Constant *, 8> EmitFunctionCallArgsArray;
1048    SmallVector<Constant *, 8> EmitArcsCallArgsArray;
1049    for (int j : llvm::seq<int>(0, CountersBySP.size())) {
1050      auto *SP = cast_or_null<DISubprogram>(CountersBySP[j].second);
1051      uint32_t FuncChecksum = Funcs.empty() ? 0 : Funcs[j]->getFuncChecksum();
1052      EmitFunctionCallArgsArray.push_back(ConstantStruct::get(
1053          EmitFunctionCallArgsTy,
1054          {Builder.getInt32(j),
1055           Options.FunctionNamesInData
1056               ? Builder.CreateGlobalStringPtr(getFunctionName(SP))
1057               : Constant::getNullValue(Builder.getInt8PtrTy()),
1058           Builder.getInt32(FuncChecksum),
1059           Builder.getInt8(Options.UseCfgChecksum),
1060           Builder.getInt32(CfgChecksum)}));
1061
1062      GlobalVariable *GV = CountersBySP[j].first;
1063      unsigned Arcs = cast<ArrayType>(GV->getValueType())->getNumElements();
1064      EmitArcsCallArgsArray.push_back(ConstantStruct::get(
1065          EmitArcsCallArgsTy,
1066          {Builder.getInt32(Arcs), ConstantExpr::getInBoundsGetElementPtr(
1067                                       GV->getValueType(), GV, TwoZero32s)}));
1068    }
1069    // Create global arrays for the two emit calls.
1070    int CountersSize = CountersBySP.size();
1071    assert(CountersSize == (int)EmitFunctionCallArgsArray.size() &&
1072           "Mismatched array size!");
1073    assert(CountersSize == (int)EmitArcsCallArgsArray.size() &&
1074           "Mismatched array size!");
1075    auto *EmitFunctionCallArgsArrayTy =
1076        ArrayType::get(EmitFunctionCallArgsTy, CountersSize);
1077    auto *EmitFunctionCallArgsArrayGV = new GlobalVariable(
1078        *M, EmitFunctionCallArgsArrayTy, /*isConstant*/ true,
1079        GlobalValue::InternalLinkage,
1080        ConstantArray::get(EmitFunctionCallArgsArrayTy,
1081                           EmitFunctionCallArgsArray),
1082        Twine("__llvm_internal_gcov_emit_function_args.") + Twine(i));
1083    auto *EmitArcsCallArgsArrayTy =
1084        ArrayType::get(EmitArcsCallArgsTy, CountersSize);
1085    EmitFunctionCallArgsArrayGV->setUnnamedAddr(
1086        GlobalValue::UnnamedAddr::Global);
1087    auto *EmitArcsCallArgsArrayGV = new GlobalVariable(
1088        *M, EmitArcsCallArgsArrayTy, /*isConstant*/ true,
1089        GlobalValue::InternalLinkage,
1090        ConstantArray::get(EmitArcsCallArgsArrayTy, EmitArcsCallArgsArray),
1091        Twine("__llvm_internal_gcov_emit_arcs_args.") + Twine(i));
1092    EmitArcsCallArgsArrayGV->setUnnamedAddr(GlobalValue::UnnamedAddr::Global);
1093
1094    FileInfos.push_back(ConstantStruct::get(
1095        FileInfoTy,
1096        {StartFileCallArgs, Builder.getInt32(CountersSize),
1097         ConstantExpr::getInBoundsGetElementPtr(EmitFunctionCallArgsArrayTy,
1098                                                EmitFunctionCallArgsArrayGV,
1099                                                TwoZero32s),
1100         ConstantExpr::getInBoundsGetElementPtr(
1101             EmitArcsCallArgsArrayTy, EmitArcsCallArgsArrayGV, TwoZero32s)}));
1102  }
1103
1104  // If we didn't find anything to actually emit, bail on out.
1105  if (FileInfos.empty()) {
1106    Builder.CreateRetVoid();
1107    return WriteoutF;
1108  }
1109
1110  // To simplify code, we cap the number of file infos we write out to fit
1111  // easily in a 32-bit signed integer. This gives consistent behavior between
1112  // 32-bit and 64-bit systems without requiring (potentially very slow) 64-bit
1113  // operations on 32-bit systems. It also seems unreasonable to try to handle
1114  // more than 2 billion files.
1115  if ((int64_t)FileInfos.size() > (int64_t)INT_MAX)
1116    FileInfos.resize(INT_MAX);
1117
1118  // Create a global for the entire data structure so we can walk it more
1119  // easily.
1120  auto *FileInfoArrayTy = ArrayType::get(FileInfoTy, FileInfos.size());
1121  auto *FileInfoArrayGV = new GlobalVariable(
1122      *M, FileInfoArrayTy, /*isConstant*/ true, GlobalValue::InternalLinkage,
1123      ConstantArray::get(FileInfoArrayTy, FileInfos),
1124      "__llvm_internal_gcov_emit_file_info");
1125  FileInfoArrayGV->setUnnamedAddr(GlobalValue::UnnamedAddr::Global);
1126
1127  // Create the CFG for walking this data structure.
1128  auto *FileLoopHeader =
1129      BasicBlock::Create(*Ctx, "file.loop.header", WriteoutF);
1130  auto *CounterLoopHeader =
1131      BasicBlock::Create(*Ctx, "counter.loop.header", WriteoutF);
1132  auto *FileLoopLatch = BasicBlock::Create(*Ctx, "file.loop.latch", WriteoutF);
1133  auto *ExitBB = BasicBlock::Create(*Ctx, "exit", WriteoutF);
1134
1135  // We always have at least one file, so just branch to the header.
1136  Builder.CreateBr(FileLoopHeader);
1137
1138  // The index into the files structure is our loop induction variable.
1139  Builder.SetInsertPoint(FileLoopHeader);
1140  PHINode *IV =
1141      Builder.CreatePHI(Builder.getInt32Ty(), /*NumReservedValues*/ 2);
1142  IV->addIncoming(Builder.getInt32(0), BB);
1143  auto *FileInfoPtr = Builder.CreateInBoundsGEP(
1144      FileInfoArrayTy, FileInfoArrayGV, {Builder.getInt32(0), IV});
1145  auto *StartFileCallArgsPtr =
1146      Builder.CreateStructGEP(FileInfoTy, FileInfoPtr, 0);
1147  auto *StartFileCall = Builder.CreateCall(
1148      StartFile,
1149      {Builder.CreateLoad(StartFileCallArgsTy->getElementType(0),
1150                          Builder.CreateStructGEP(StartFileCallArgsTy,
1151                                                  StartFileCallArgsPtr, 0)),
1152       Builder.CreateLoad(StartFileCallArgsTy->getElementType(1),
1153                          Builder.CreateStructGEP(StartFileCallArgsTy,
1154                                                  StartFileCallArgsPtr, 1)),
1155       Builder.CreateLoad(StartFileCallArgsTy->getElementType(2),
1156                          Builder.CreateStructGEP(StartFileCallArgsTy,
1157                                                  StartFileCallArgsPtr, 2))});
1158  if (auto AK = TLI->getExtAttrForI32Param(false))
1159    StartFileCall->addParamAttr(2, AK);
1160  auto *NumCounters =
1161      Builder.CreateLoad(FileInfoTy->getElementType(1),
1162                         Builder.CreateStructGEP(FileInfoTy, FileInfoPtr, 1));
1163  auto *EmitFunctionCallArgsArray =
1164      Builder.CreateLoad(FileInfoTy->getElementType(2),
1165                         Builder.CreateStructGEP(FileInfoTy, FileInfoPtr, 2));
1166  auto *EmitArcsCallArgsArray =
1167      Builder.CreateLoad(FileInfoTy->getElementType(3),
1168                         Builder.CreateStructGEP(FileInfoTy, FileInfoPtr, 3));
1169  auto *EnterCounterLoopCond =
1170      Builder.CreateICmpSLT(Builder.getInt32(0), NumCounters);
1171  Builder.CreateCondBr(EnterCounterLoopCond, CounterLoopHeader, FileLoopLatch);
1172
1173  Builder.SetInsertPoint(CounterLoopHeader);
1174  auto *JV = Builder.CreatePHI(Builder.getInt32Ty(), /*NumReservedValues*/ 2);
1175  JV->addIncoming(Builder.getInt32(0), FileLoopHeader);
1176  auto *EmitFunctionCallArgsPtr = Builder.CreateInBoundsGEP(
1177      EmitFunctionCallArgsTy, EmitFunctionCallArgsArray, JV);
1178  auto *EmitFunctionCall = Builder.CreateCall(
1179      EmitFunction,
1180      {Builder.CreateLoad(EmitFunctionCallArgsTy->getElementType(0),
1181                          Builder.CreateStructGEP(EmitFunctionCallArgsTy,
1182                                                  EmitFunctionCallArgsPtr, 0)),
1183       Builder.CreateLoad(EmitFunctionCallArgsTy->getElementType(1),
1184                          Builder.CreateStructGEP(EmitFunctionCallArgsTy,
1185                                                  EmitFunctionCallArgsPtr, 1)),
1186       Builder.CreateLoad(EmitFunctionCallArgsTy->getElementType(2),
1187                          Builder.CreateStructGEP(EmitFunctionCallArgsTy,
1188                                                  EmitFunctionCallArgsPtr, 2)),
1189       Builder.CreateLoad(EmitFunctionCallArgsTy->getElementType(3),
1190                          Builder.CreateStructGEP(EmitFunctionCallArgsTy,
1191                                                  EmitFunctionCallArgsPtr, 3)),
1192       Builder.CreateLoad(EmitFunctionCallArgsTy->getElementType(4),
1193                          Builder.CreateStructGEP(EmitFunctionCallArgsTy,
1194                                                  EmitFunctionCallArgsPtr,
1195                                                  4))});
1196  if (auto AK = TLI->getExtAttrForI32Param(false)) {
1197    EmitFunctionCall->addParamAttr(0, AK);
1198    EmitFunctionCall->addParamAttr(2, AK);
1199    EmitFunctionCall->addParamAttr(3, AK);
1200    EmitFunctionCall->addParamAttr(4, AK);
1201  }
1202  auto *EmitArcsCallArgsPtr =
1203      Builder.CreateInBoundsGEP(EmitArcsCallArgsTy, EmitArcsCallArgsArray, JV);
1204  auto *EmitArcsCall = Builder.CreateCall(
1205      EmitArcs,
1206      {Builder.CreateLoad(
1207           EmitArcsCallArgsTy->getElementType(0),
1208           Builder.CreateStructGEP(EmitArcsCallArgsTy, EmitArcsCallArgsPtr, 0)),
1209       Builder.CreateLoad(EmitArcsCallArgsTy->getElementType(1),
1210                          Builder.CreateStructGEP(EmitArcsCallArgsTy,
1211                                                  EmitArcsCallArgsPtr, 1))});
1212  if (auto AK = TLI->getExtAttrForI32Param(false))
1213    EmitArcsCall->addParamAttr(0, AK);
1214  auto *NextJV = Builder.CreateAdd(JV, Builder.getInt32(1));
1215  auto *CounterLoopCond = Builder.CreateICmpSLT(NextJV, NumCounters);
1216  Builder.CreateCondBr(CounterLoopCond, CounterLoopHeader, FileLoopLatch);
1217  JV->addIncoming(NextJV, CounterLoopHeader);
1218
1219  Builder.SetInsertPoint(FileLoopLatch);
1220  Builder.CreateCall(SummaryInfo, {});
1221  Builder.CreateCall(EndFile, {});
1222  auto *NextIV = Builder.CreateAdd(IV, Builder.getInt32(1));
1223  auto *FileLoopCond =
1224      Builder.CreateICmpSLT(NextIV, Builder.getInt32(FileInfos.size()));
1225  Builder.CreateCondBr(FileLoopCond, FileLoopHeader, ExitBB);
1226  IV->addIncoming(NextIV, FileLoopLatch);
1227
1228  Builder.SetInsertPoint(ExitBB);
1229  Builder.CreateRetVoid();
1230
1231  return WriteoutF;
1232}
1233
1234Function *GCOVProfiler::insertReset(
1235    ArrayRef<std::pair<GlobalVariable *, MDNode *>> CountersBySP) {
1236  FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx), false);
1237  Function *ResetF = M->getFunction("__llvm_gcov_reset");
1238  if (!ResetF)
1239    ResetF = Function::Create(FTy, GlobalValue::InternalLinkage,
1240                              "__llvm_gcov_reset", M);
1241  else
1242    ResetF->setLinkage(GlobalValue::InternalLinkage);
1243  ResetF->setUnnamedAddr(GlobalValue::UnnamedAddr::Global);
1244  ResetF->addFnAttr(Attribute::NoInline);
1245  if (Options.NoRedZone)
1246    ResetF->addFnAttr(Attribute::NoRedZone);
1247
1248  BasicBlock *Entry = BasicBlock::Create(*Ctx, "entry", ResetF);
1249  IRBuilder<> Builder(Entry);
1250
1251  // Zero out the counters.
1252  for (const auto &I : CountersBySP) {
1253    GlobalVariable *GV = I.first;
1254    Constant *Null = Constant::getNullValue(GV->getValueType());
1255    Builder.CreateStore(Null, GV);
1256  }
1257
1258  Type *RetTy = ResetF->getReturnType();
1259  if (RetTy->isVoidTy())
1260    Builder.CreateRetVoid();
1261  else if (RetTy->isIntegerTy())
1262    // Used if __llvm_gcov_reset was implicitly declared.
1263    Builder.CreateRet(ConstantInt::get(RetTy, 0));
1264  else
1265    report_fatal_error("invalid return type for __llvm_gcov_reset");
1266
1267  return ResetF;
1268}
1269
1270Function *GCOVProfiler::insertFlush(Function *ResetF) {
1271  FunctionType *FTy = FunctionType::get(Type::getVoidTy(*Ctx), false);
1272  Function *FlushF = M->getFunction("__llvm_gcov_flush");
1273  if (!FlushF)
1274    FlushF = Function::Create(FTy, GlobalValue::InternalLinkage,
1275                              "__llvm_gcov_flush", M);
1276  else
1277    FlushF->setLinkage(GlobalValue::InternalLinkage);
1278  FlushF->setUnnamedAddr(GlobalValue::UnnamedAddr::Global);
1279  FlushF->addFnAttr(Attribute::NoInline);
1280  if (Options.NoRedZone)
1281    FlushF->addFnAttr(Attribute::NoRedZone);
1282
1283  BasicBlock *Entry = BasicBlock::Create(*Ctx, "entry", FlushF);
1284
1285  // Write out the current counters.
1286  Function *WriteoutF = M->getFunction("__llvm_gcov_writeout");
1287  assert(WriteoutF && "Need to create the writeout function first!");
1288
1289  IRBuilder<> Builder(Entry);
1290  Builder.CreateCall(WriteoutF, {});
1291  Builder.CreateCall(ResetF, {});
1292
1293  Type *RetTy = FlushF->getReturnType();
1294  if (RetTy->isVoidTy())
1295    Builder.CreateRetVoid();
1296  else if (RetTy->isIntegerTy())
1297    // Used if __llvm_gcov_flush was implicitly declared.
1298    Builder.CreateRet(ConstantInt::get(RetTy, 0));
1299  else
1300    report_fatal_error("invalid return type for __llvm_gcov_flush");
1301
1302  return FlushF;
1303}
1304